Ultimate Outlet vs. PS Audio P300

I just added a P300 to my system. It's an addition to my two existing HC Ultimate Outlets. I noticed a significant improvement in dynamics, background, and soundstage. Bass, in particular, is tighter and the notes are more defined. I'm already looking forward to upgrading to the P500, due the the added power capibilities and more user-friendly dimensions.

I looking to add a power conditioner to my system. I have added a dedicated 20 amp line and have my amp (ATI 1807)and my PrePro (Anthen avm 30) plugged in. I'm looking at the PS audio Duet and the Shunyata Guardian 4. Is there $200.00 worth of difference between the two. Both say they won't restrict power and this is the main thing I'm looking for. I have a Monster 2000 right now handeling my source equiptment, and it works fine. But It kills the amp.

I have both. Ultimate outlet mostly impacts and cleans upper frequencies, making the soundprint more detailed and faster. The P300 powerplant has a different impact: it makes the sound more palpable and gives weight to instruments, increases microdynamic, closer to live music. P300 is a very worthwile ivestment for source components. It makes my ML 39 a very analogue sounding source, and my Alesis Masterlink to be a fairly enjoyable component (without it especially the last one could be very annoyingly boring sounding machine).